1. Field of The Invention
The present invention relates to an aluminum alloy, more particularly, to a high strength aluminum alloy and for pressure casting, such as pressure die casting, gravity die casting, and squeeze casting. The aluminum alloy is heat treated to obtain its superior mechanical properties.
2. Description of the Related Art
Al-Si-Cu-Mg alloy members or parts including 5 to 13 wt % silicon, 1 to 5 wt % copper, and 0.1 to 0.5 wt % magnesium are formed by pressure casting and then subjected to T6 treatment resulting in a tensile strength of approximately 40 kg/mm.sup.2 and an elongation of from 5% to 10%. These are thus suitable as engine parts of automobile and ships, safety parts, mechanical parts, and the like.
In the T6 treatment, the members are subjected to solution heat treatment where theyaare held at a temperature of from 480.degree. C. to 540.degree. C. for 4 to 10 hours quenched and then subjected to artificial aging at a temperature of from 150.degree. C. to 200.degree. C. for 3 to 8 hours. Thus, the treating time is relatively long and is undesirable in terms of production efficiency. A typical Al-Si-Cu-Mg alloy now in use, incidentally, is AC4D [JIS H 5202 (1977)], corresponding to AA355.0.